Today I updated to current dovecot-1.1 hg tree and I got many of these assertion failures:
file istream.c: line 303 (i_stream_read_data): assertion failed: (stream->stream_errno != 0) (gdb) bt full #0 0x00352402 in __kernel_vsyscall () No symbol table info available. #1 0x0043ed20 in raise () from /lib/libc.so.6 No symbol table info available. #2 0x00440631 in abort () from /lib/libc.so.6 No symbol table info available. #3 0x080f6968 in default_fatal_finish (type=LOG_TYPE_PANIC, status=0) at failures.c:150 backtrace = 0x906d950 "/usr/libexec/dovecot/imap [0x80f6946] -> /usr/libexec/dovecot/imap [0x80f7207] -> /usr/libexec/dovecot/imap(i_fatal+0) [0x80f6ac0] -> /usr/libexec/dovecot/imap(i_stream_read_data+0. #4 0x080f7207 in i_internal_fatal_handler (type=LOG_TYPE_PANIC, status=0, fmt=0x8124778 "file %s: line %d (%s): assertion failed: (%s)", args=0xbfe643a4 "mG\022\b/\001") at failures.c:430 No locals. #5 0x080f6ac0 in i_panic (format=0x8124778 "file %s: line %d (%s): assertion failed: (%s)") at failures.c:197 args = 0xbfe643a4 "mG\022\b/\001" #6 0x080fcb64 in i_stream_read_data (stream=0x9094a08, data_r=0xbfe64444, size_r=0xbfe64440, threshold=0) at istream.c:303 ret = -1 read_more = false __PRETTY_FUNCTION__ = "i_stream_read_data" #7 0x08065ba1 in imap_fetch_send (ctx=0x90716e0, output=0x90714ec, input=0x9094a08, cr_skipped=false, virtual_size=169, add_missing_eoh=false, last_cr=0x9071734) at imap-fetch-body.c:132 msg = (const unsigned char *) 0x0 i = 3219539032 size = 0 vsize_left = 169 sent = 0 ret = 581237648214344776 add = 16 '\020' blocks = false #8 0x08065d7f in fetch_stream_send (ctx=0x90716e0) at imap-fetch-body.c:217 ret = 151603720 #9 0x080660e8 in fetch_stream (ctx=0x90716e0, size=0x908efc4) at imap-fetch-body.c:293 input = (struct istream *) 0x10b8df #10 0x08066225 in fetch_data (ctx=0x90716e0, body=0x9071cd8, size=0x908efc4) at imap-fetch-body.c:318 str = (string_t *) 0x906cc18 #11 0x08066ac7 in fetch_body_mime (ctx=0x90716e0, mail=0x908e9e8, body=0x9071cd8) at imap-fetch-body.c:555 part = (const struct message_part *) 0x908efb0 section = 0x9071d12 "MIME" __PRETTY_FUNCTION__ = "fetch_body_mime" #12 0x08064bad in imap_fetch_more (ctx=0x90716e0) at imap-fetch.c:309 h = (const struct imap_fetch_context_handler *) 0x90718c8 _data_stack_cur_id = 4 client = (struct client *) 0x9071368 handlers = (const struct imap_fetch_context_handler *) 0x9071850 count = 7 ret = 1 __PRETTY_FUNCTION__ = "imap_fetch_more" #13 0x08064dd4 in imap_fetch (ctx=0x90716e0) at imap-fetch.c:361 ret = 0 __PRETTY_FUNCTION__ = "imap_fetch" #14 0x0805c792 in cmd_fetch (cmd=0x9071600) at cmd-fetch.c:152 ctx = (struct imap_fetch_context *) 0x90716e0 args = (const struct imap_arg *) 0x9075688 search_arg = (struct mail_search_arg *) 0x9071678 messageset = 0x9075750 "4068" ret = 151455048 #15 0x08061173 in cmd_uid (cmd=0x9071600) at cmd-uid.c:26 command = (struct command *) 0x907068c cmd_name = 0x9075738 "fetch" #16 0x08062534 in client_command_input (cmd=0x9071600) at client.c:580 client = (struct client *) 0x9071368 command = (struct command *) 0x23 __PRETTY_FUNCTION__ = "client_command_input" #17 0x08062769 in client_command_input (cmd=0x9071600) at client.c:629 client = (struct client *) 0x9071368 command = (struct command *) 0x9070668 __PRETTY_FUNCTION__ = "client_command_input" #18 0x08062867 in client_handle_next_command (client=0x9071368, remove_io_r=0xbfe64765) at client.c:670 size = 132 #19 0x080628a3 in client_handle_input (client=0x9071368) at client.c:680 _data_stack_cur_id = 3 ret = 7 remove_io = false handled_commands = false #20 0x08062a31 in client_input (client=0x9071368) at client.c:725 cmd = (struct client_command_context *) 0x4e7408 output = (struct ostream *) 0x90714ec bytes = 132 __PRETTY_FUNCTION__ = "client_input" #21 0x08101115 in io_loop_handler_run (ioloop=0x906f9b0) at ioloop-epoll.c:203 ctx = (struct ioloop_handler_context *) 0x906faa8 events = (struct epoll_event *) 0x906fae8 event = (const struct epoll_event *) 0x906fae8 list = (struct io_list *) 0x9071568 io = (struct io_file *) 0x9071548 tv = {tv_sec = 1799, tv_usec = 999874} events_count = 3 t_id = 2 msecs = 1800000 ret = 1 i = 0 j = 0 call = true #22 0x081003ac in io_loop_run (ioloop=0x906f9b0) at ioloop.c:320 No locals. #23 0x0806debd in main (argc=1, argv=0xbfe648c4, envp=0xbfe648cc) at main.c:293 No locals.